patriots day, also tax day. that could've got people up in arms. it could be a foreign type. so you leave all the options, all the possibilities open and let the evidence and the cctv cameras and the witnesses will bring you to your suspects. >> chief, how extensive is the camera network in boston? obviously, when something happens in london you can -- >> dial it up. >> you can dial it up pretty quick. there are a few streets in london that aren't on close circuit tv. do you know what the situation is in boston? >> yeah, my sense is most american cities, new york is going that route. there's nothing like london and belfast. those two cities have complete integrated system and it's almost nothing without it being captured on cctv cameras. as a matter of fact, back in 2005 in london, they were able to follow those guys from outside of london all the way into london to the subways and to the bus. so there the cctv cameras were absolutely invaluable in the investigation. my sense is boston -- they will have some cctv cameras. filming the very end of the finish line and then you h